Many online content publishing systems rely on cascading style sheets (“CSS”) that includes style rules which tell a browser running on a desktop PC (personal computer), or a portable device like a mobile phone or pocket PC, how to present a document such as a web page. Typically, a CSS may be optimized by hand to eliminate unused styles for a particular scenario, or to create a customized version of the CSS for a specific target client agent. For example, a CSS may be customized to a specific desktop browser such as Microsoft Internet Explorer® or Mozilla Firefox®.
In comparison to the desktop PC environment, variations in CSS implementations for browsers on mobile devices are generally more numerous. Mobile devices vary widely in their page rendering capabilities and commonly employ different browser types and support different markup languages that are used to define pages. Mobile devices typically have limited memory resources and the networks on which they operate are often bandwidth-constrained so it is generally desirable to minimize the size of the CSS used for the pages. It is not reasonable, however, to require the use of multiple different CSS files per device or to employ multiple CSS versions for a given page in order to optimize the page size to a specific device. Accordingly, existing mobile content solutions tend to keep use of CSS to a minimum or use a one-size-fits-all approach to enable the CSS to be applied to as large a number of devices as possible. While such solutions are satisfactory in some applications, the richness of the user experience in other applications may be significantly diminished.
This Background is provided to introduce a brief context for the Summary and Detailed Description that follow. This Background is not intended to be an aid in determining the scope of the claimed subject matter nor be viewed as limiting the claimed subject matter to implementations that solve any or all of the disadvantages or problems presented above.